Weld fasteners such as weld nuts, studs, posts, screws, or other weld fasteners are pieces of externally-threaded or internally-threaded fastening hardware that are welded around a perimeter of an opening in a panel or other work piece, thus securing the weld fastener to the work piece. Once the weld fastener has been secured in this manner, another work piece can be joined to the first work piece using a mating nut or bolt, depending on the configuration of the weld fastener. For example, in an automotive vehicle panel having an installed weld stud, the panel can be placed immediately adjacent to an opening or hole in another vehicle panel such that the weld stud protrudes through the hole. A standard nut can then be threaded onto the free end of the weld stud and sufficiently tightened to thereby securely join the adjacent panels. In the same manner, a weld nut can be welded into a hole formed in a vehicle panel, with a threaded fastener inserted into the weld nut through a hole in another vehicle panel to thereby join the adjacent panels.
Due to the additional strength provided by the weld, weld fasteners are relatively strong and durable compared to conventional non-welded fasteners. However, the welded nature of a weld fastener also provides a number of challenges. For example, it can be difficult to weld a weld fastener to the work piece precisely enough to provide the installed fastener with a desired centerline or offset angle relative to the plane of the work piece. Therefore, the actual centerline of the installed weld fastener can be offset from the desired or specified angle. Moreover, certain characteristics of an installed weld fastener can be difficult to measure accurately using contact-type or noncontact type dimensional measurement sensors or devices due largely to the limited surface area and inherent variation of the individual threads of the weld fastener.